Chapter 9: Muscles and Muscle Tissue

STUDY

PLAY

Once a motor neuron has fired, all the muscle fibers in a muscle contract.

FALSE

A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.

FALSE

Peristalsis is characteristic of smooth muscle.

TRUE

A contraction in which the muscle does not shorten but its tension increases is called isometric.

TRUE

During isotonic contraction, the heavier the load, the faster the velocity of contraction.

FALSE

One of the important functions of skeletal muscle contraction is production of heat.

TRUE

Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.

TRUE

A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.

TRUE

The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.

TRUE

Which muscle cells have the greatest ability to regenerate?A) skeletalB) cardiacC) smoothD) no muscle can regenerate

C) smooth

Most muscles contain ________.A) muscle fibers of the same typeB) a mixture of fiber typesC) a predominance of slow oxidative fibersD) a predominance of fast oxidative fibers

B) a mixture of fiber types

Which of the following is not a usual result of resistance exercise?A) increase in the efficiency of the respiratory systemB) increase in the efficiency of the circulatory systemC) increase in the number of muscle cellsD) increase in the number of myofibrils within the muscle cells

C) increase in the number of muscle cells

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the events of excitation-contraction coupling occur.A) contraction B) relaxation C) latent D) refractory

C) latent

Creatine phosphate functions in the muscle cell by ________.A) forming a temporary chemical compound with myosinB) forming a chemical compound with actinC) inducing a conformational change in the myofilamentsD) storing energy that will be transferred to ADP to resynthesize ATP

D) storing energy that will be transferred to ADP to resynthesize ATP

The major function of the sarcoplasmic reticulum in muscle contraction is to ________.A) make and store phosphocreatineB) synthesize actin and myosin myofilamentsC) provide a source of myosin for the contraction processD) regulate intracellular calcium concentration

D) regulate intracellular calcium concentration

The striations of a skeletal muscle cell are produced, for the most part, by____A) a difference in the thickness of the sarcolemmaB) the arrangement of myofilamentsC) the sarcoplasmic reticulumD) the T tubules

B) the arrangement of myofilaments

Which of the following are composed of myosin?A) thick filamentsB) thin filamentsC) all myofilamentsD) Z discs

Which of the following surrounds the individual muscle cell?A) perimysiumB) endomysiumC) epimysiumD) fascicle

B) endomysium

Rigor mortis occurs because ________.A) the cells are deadB) sodium ions leak out of the muscleC) no ATP is available to release attached actin and myosin moleculesD) proteins are beginning to break down, thus preventing a flow of calcium ions

C) no ATP is available to release attached actin and myosin molecules

Which of the choices below does not describe how recovery oxygen uptake (oxygen deficit) restores metabolic conditions?A) converts lactic acid back into glycogen stores in the liverB) resynthesizes creatine phosphate and ATP in muscle fibersC) increases the level of lactic acid in the muscleD) replaces the oxygen removed from myoglobin

C) increases the level of lactic acid in the muscle

The oxygen-binding protein found in muscle cells is ________.A) hemoglobinB) ATPC) myoglobinD) immunoglobin

one functional unit of a skeletal muscle is_____A) a sarcomereB) a myofilamentC) a myofibrilD) the sarcoplasmic reticulum

A) a sarcomere

The the functional role of the T tubules is to____A) stabilize the G and F actinB) enhance cellular communication during muscle contractionC) hold cross bridges in place in a resting muscleD) synthesize ATP to provide energy for muscle contraction

B) enhance cellular communication during muscle contraction

The role of calcium ions in muscle contraction is to_____A) form hydroxyapatite crystalsB) reestablish glycogen storesC) bind to regulatory sites on troponin to remove contraction inhibitionD) increase levels of myoglobin

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.A) a strong baseB) stearic acidC) hydrochloric acidD) lactic acid

D) lactic acid

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?A) relaxation periodB) refractory periodC) latent periodD) fatigue period

B) refractory period

In an isotonic contraction, the muscle ________.A) changes in length and moves the "load"B) does not change in length but increases tensionC) never converts pyruvate to lactateD) rapidly resynthesizes creatine phosphate and ATP

A) changes in length and moves the "load"

The muscle cell membrane is called the ________.A) endomysiumB) sarcolemmaC) perimysiumD) epimysium

B) sarcolemma

Smooth muscle is characterized by all of the following except ________.A) it appears to lack troponinB) there are more thick filaments than thin filamentsC) there are no sarcomeresD) there are noncontractile intermediate filaments that attach to dense bodies within the cell

B) there are more thick filaments than thin filaments

Muscle tissue has all of the following properties except ________.A) secretionB) contractilityC) extensibilityD) excitability

A) secretion

Which of the following statements is true?A) Cardiac muscle cells have many nuclei.B) Smooth muscle cells have T tubules.C) Striated muscle cells are long and cylindrical with many nuclei.D) Cardiac muscle cells are found in the heart and large blood vessels.

C) Striated muscle cells are long and cylindrical with many nuclei.

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.A) the citric acid cycleB) glycolysisC) hydrolysisD) the electron transport chain

B) glycolysis

The sliding filament model of contraction involves ________.A) actin and myosin sliding past each other and partially overlappingB) the shortening of thick filaments so that thin filaments slide pastC) actin and myosin shortening but not sliding past each otherD) the Z discs sliding over the myofilaments

A) actin and myosin sliding past each other and partially overlapping

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?A) calcium ions returning to the terminal cisternaeB) the tropomyosin blocking the myosin once full contraction is achievedC) acetylcholinesterase destroying the AChD) the action potential stops going down the overloaded T tubules